FIG. 1 shows an aircraft 10 which is immobile on the ground. The aircraft is powered with electricity by means of a generator set 20 via a power supply cable 30 which has several electrical conductors and is provided at its end with an end connector 40 having an electrical contact for each electrical conductor.
In order to allow connection to the generator set 20, the aircraft 10 has a connection terminal 50 having, for each electrical conductor, an electrical contact downstream of which a conductor 14 is connected embedded in the aircraft 10 and to which at least one electrical component 12 of the aircraft 10 is connected.
The connection between the end connector 40 and the connection terminal 50 is performed by means of an extension socket 60.
FIG. 2 shows an example of an extension socket 60 comprising a body 61 with a first connector 62 comprising, for each electrical contact of the end connector 40, an electrical contact which is connected electrically to the said electrical contact of the end connector 40, and a second connector 64 comprising, for each electrical conductor, an electrical contact 65 (in this case female) which is electrically connected to the electrical contact of the first corresponding connector 62 and which is designed to be connected to an electrical contact (in this case male) of the connection terminal 50.
The extension socket 60 allows here the connection of six electrical conductors which are indicated here by the reference letters A, B, C, N, E and F. The connection terminal 50 thus comprises, for each electrical conductor A, B, C, N, E, F, an embedded conductor 14 which is electrically connected to an electrical conductor A, B, C, N, E, F via the second connector 64 and the connection terminal 50.
The extension socket 60 has a third connector 66 which, for each electrical conductor, has a female electrical contact 68 which is electrically connected to the electrical contact of the first connector 62 connected to the said electrical conductor and which allows for example the connection of a connecting member of a multimeter.
The connection of the generator set 20 to the aircraft 10 forms a loop.
When lightning strikes the ground close to the aircraft 10, a part of the magnetic field induced by the lightning generates a voltage drop in the loop, creating an inductive coupling which generates an electrical overvoltage in the power supply cable 30. This electrical overvoltage is propagated as far as the aircraft 10 with the risk of damaging certain electrical components 12 on-board the aircraft 10.